In a medium bowl, cover the rice with cold water. Set aside.
Line a plate with two paper towels. Heat the olive oil in a large pot over high heat. Add the onions and cook, stirring constantly, until the onions are deeply browned and start to crisp around the edges, about 20 minutes. Transfer to the plate and set aside. They will continue to crisp as they cool.
Add the lentils to another pot, add water and stir to combine. Bring everything to a boil, then reduce the heat to medium-low and cover with a tight-fitting lid. Cook for 15 minutes.
Drain the soaked rice, rinse and transfer it to the pot with the lentils along with the salt. Stir once, then cover again with a tight-fitting lid and cook undisturbed for 15 minutes.
Remove the pot from the heat. Rest, covered, for 5 minutes longer. Add the cumin and fluff the rice and lentils with a fork to combine.
Spoon the crispy sliced onions on top of the mujadara. Serve warm, with cucumber yogurt sauce if desired.
Video
Notes
Storage: Store any leftovers in an airtight container. They will last about 4-5 days in the fridge.Freezing Instructions: You can freeze the mujadara for up to 3 months. To re-heat, thaw in the fridge overnight and microwave until heated through.Make Ahead Tips: You can chop the onions in advance up to a day before and even caramelize the sliced onions beforehand in order to reduce the prep time.Sourcing: You can find the brown and green lentils at Middle Eastern markets, natural-foods stores or even in large supermarkets, often located with other Middle Eastern ingredients.Substitutes: For best results, follow the recipe as is. However here are some common substitutes that would work well in this recipe.
Instead of brown lentils, you can use green lentils.
Instead of white rice, you can use brown rice or bulgur/cracked wheat.